Mesoscopic spiral nanoplates formed by porphyrin-spaced coordination frameworks for enhanced H2O2 photosynthesis

Abstract

Although tremendous efforts have been devoted to regulating the morphology of metal–organic frameworks (MOFs), it is still a substantial challenge to achieve chirality at the crystal morphological level. This work presents a bottom-up synthetic approach to produce chiral morphological bismuth-based porphyrin MOFs, featuring a unique surface morphology – a square spiral terrace-shaped crystal that exhibits mesoscopic mirror-symmetry breaking. Compared with bulk samples, screw dislocation defects could promote the anisotropic growth of the square spiral terrace-shaped nanoplates under conditions of low supersaturation concentrations and in the presence of polyvinyl pyrrolidone (PVP). To assess the effect of the anisotropic morphology on the properties, photocatalytic hydrogen peroxide (H₂O₂) production experiments under pure water and oxygen conditions (blue LED illumination, λ = 455 nm) were carried out. The experimental results showed that the screw dislocation nanoplates displayed 1.5 times higher photocatalytic activity (156.22 μM h⁻¹) than that of bulk samples (106.24 μM h⁻¹). This may be attributed to the better dispersion in water and fully exposed catalytically active sites of the screw dislocation nanoplates. These findings provide novel insights for obtaining MOFs with a chiral morphology and improving the photocatalytic H₂O₂ generation based on morphological control.